1. Field of the Invention
The present invention relates generally to a container for the preparation of carbonated liquids and more particularly pertains to a container enabling consumer preparation of carbonated beverages, either at home or as otherwise convenient, having substantially the same palatability and effervescence as bottled or canned carbonated beverages. In greater detail, the present invention relates to a container designed to prepare a carbonated beverage from an effervescent acid carbonate couple while providing for separation from the beverage of the resultant salts of the carbonation reaction.
2. Discussion of the Prior Art
Prior art approaches to commercialize point-of-consumption or at-home preparation of carbonated beverages have not met with sustained success over the years. The principal shortcoming of the several techniques available in the art is that consumer-prepared carbonated beverages have been significantly inferior in one or more aspects to bottled or canned carbonated beverages available in stores or supermarkets. Common complaints leveled at carbonated beverages prepared by consumers are that the quality and quantity of the carbonation (the bubble size and duration of effervescence) do not compare favorably with commercially available, bottled carbonated beverages, and that the palatability of the beverages suffer from the adverse effects of the carbonating reactants, when that approach to carbonation is pursued.
However, consumer preparation of carbonated beverages offers significant advantages over prepared package liquid carbonated beverages for several reasons: the requirement for glass, metal or other bulky containers is avoided; the steps of bottling, shipping and storing carbonated beverages consisting of a major percentage of water are eliminated, and accordingly the utility in terms of portability to the use is greatly enhanced. Thus, homemakers, campers, backpackers, hunters, fishermen, outdoor spectators and travellers can enjoy a carbonated beverage without having to transport bulky and heavy quantities of canned or bottled drinks. Further, disposable or returnable cans and bottles would no longer be of major concern to environmentalisit who have been seeking ways to conserve both the country's natural resources and beauty.
The art or concept of carbonating a beverage by the addition of water or suitable liquids to dry chemicals is well developed in the prior art technology. Some of the earlier publications in this field recommend admixing an acid, such as tartaric acid, with a carbonate, such as baking soda, and a flavoring so as to produce a carbonated beverage when the mix is dissolved in water. A carbonation system of this nature is generally economical to produce, and affords availability of a wide choice of safe carbonates and acids which are constituted of commonly used food ingredients. Moreover, many carbonates and acids have properties which are compatible with those of other commonly used ingredients in dry beverage mixes.
Unfortunately, a carbonation system of this type is subject to several disadvantages and drawbacks. The rate of carbonation of the beverage is often unsatisfactory, such as when the powder is admixed with water, which results in an initial excessive liberation of carbon dioxide, producing attendant foaming of the beverage, followed by a period of diminishing gas generation in which the carbonation of the beverage is at an inadequate level. Further, the taste of the resultant beverage is often adversely affected by the products which are formed during the chemical carbonation reaction so as to produce a salty, acidic tasting beverage. Also, the visual appearance of the beverage is frequently adversely affected by being rendered murky through the presence of undissolved salts which are formed during the reaction. Furthermore, the shelf life of the dry mix is often of an insufficient duration so as to render the dry mix unsuitable for numerous commerical applications.
Many approaches have been suggested by the prior art which are designed to overcome the aforementioned deficiencies. For instance, it has been suggested that the carbonation rate may be controlled by the application of coating agents, such as gums, to the dry powders, or by applying special granulation techniques to the powders. Additionally, the taste and appearance of dry mix beverages have been improved by the introduction of numerous new acidic and carbonate compounds. Further, the shelf life of the dry mixture has been extended by applying agglomeration and other blending techniques to the mixture and by protecting the carbonating compounds with chemical agents.
The patent art also includes a significant number of dry compositions for use in preparing carbonated beverages at home. In most of these compositions, sources of carbonate and acid are combined with sweeteners and a source of flavor so that upon addition of the composition to a glass of water, the materials react to yield carbon dioxide, thereby resulting in carbonation of the beverage. Alther U.S. Pat. No. 2,603,569 discloses the carbonation of a citric acid-sucrose complex with a sodium bicarbonate-sucrose complex. Hughes U.S. Pat. No. 2,742,363 discloses the use of the combination of an alkali metal bicarbonate and a sulfonic acid ion exchange resin in its hydrogen form. Diller U.S. Pat. Nos. 2,851,359 and 2,953,459 disclose the combination of a highly soluble phosphate and a slowly soluble phosphate with an alkali metal or ammonium carbonate or bicarbonate to prolong the ebullition of the beverage. Mitchell et al U.S. Pat. No. 3,241,977 discloses chemical carbonation with citric, adipic or tartaric acid in a finely divided form, which are alleged to approximate the carbonation sensation of cola-type beverages sold in air-tight bottles or cans and produced by a saturated solution containing several volumes of carbon dioxide. Feldman et al U.S. Pat. No. 3,441,417 discloses a dry beverage composition adapted to be reconstituted with water to produce an effervescent beverage. The composition includes an essential carbonating ingredient, an organic compound having a carbonic acid anhydride group, capable of controlled hydrolysis in water to release carbon dioxide at a substantially uniform rate. Fritzberg et al U.S. Pat. No. 3,667,962 discloses a carbonation composition utilizing two distinct bodies formed from an aqueous solution of a saccharide, one containing an edible food acid and the other an edible bicarbonate. Upon addition to water, the two tablets dissolve quickly and react to produce carbon dioxide.
Many of the dry powder chemical mixtures have a common and acknowledged defect, an unpleasant taste in the beverage directly resulting from the components of the powder. Hughes U.S. Pat. No. 2,742,363 and Hovey U.S. Pat. No. 3,476,520 attempt to solve this problem by placing the chemicals in a container which is pervious to gas and water but impervious to solid reactants and by-products, as explained in further detail, infra. Barnes et al U.S. Pat. No. 2,975,603 takes another approach by utilizing carbonated ice containing at least 25 milliliters of carbon dioxide per gram of ice as the source of carbonation. Sampson et al U.S. Pat. No. 3,888,998 and Whyte et al U.S. Pat. Nos. 3,992,493 and 4,025,655 and Liepa et al U.S. Pat. Nos. 4,007,134, 4,110,255 and 4,147,808 disclose various carbonation methods, compositions and devices whereby carbon dioxide containing molecular sieves are used to carbonate aqueous solutions.
U.S. Pat. No. 4,316,409 issued Feb. 23, 1983 for Carbonated Beverage Container and U.S. Pat. No. 4,285,977, issued Aug. 25, 1981 for Process for Preparing Carbonated Liquids and both commonly assigned herewith, are also considered to be pertinent to the present invention. U.S. Pat. No. 4,316,409 discloses a closed pressurized container for producing a carbonated beverage by providing for contact therein of water and a briquette of carbonated ice. The pressurized container is a rigid receptable in the shape of a wide mouth bottle adapted to receive a large cap or cover. A perforated basket is mounted inside the cover, and is accessible to water in the bottle when that vessel is turned upside down to an inverted position. A spring loaded, manually operated valve is provided in the cover to permit venting of carbon dioxide from the interior thereof after the water-based mixture within the container has become sufficiently carbonated by absorbing carbon dioxide released by contact of water with the carbonated ice briquette. U.S. Pat. No. 4,285,977 covers the process for carbonation using such a container.
Madsen U.S. Pat. No. 2,205,147 illustrates a carbonating container wherein a tablet of acid such as citric acid and a tablet of bicarbonate of soda are introduced into a compartment at the top of the container, from which the tablets are dispensed by the use into separate water-containing chambers in the container. The separated acid and carbonate components are mixed upon tilting of the container, which results in pouring of equal quantities of each into a glass. No attempt is made herein to separate the salts of the reaction from the resultant carbonated beverage.
Hughes U.S. Pat. No. 2,742,363 discloses a cup type of container having a quantity of ion exchange resin and other materials in the base thereof which includes an acid and an alkali metal bicarbonate. After mixing with water, a filter member is moved to an extended position across the cup which permits the resultant beverage to pass therethrough but traps resin particles employed in the production of carbonic acid.
Hovey U.S. Pat. No. 3,492,671 illustrates a container for producing carbonated beverages from water and reactants such as sodium bicarbonate and citric acid in which the reactants are placed within a cylindrical hollow member which is then inserted into the container. A filter of sintered glass is positioned at the top of the cylindrical member to permit carbon dioxide to pass therethrough, but retains in the cylindrical member the salts and other by-products of the chemical reaction. Although the object of this patent is similar to that of the present invention, the structure designed to achieve that result is substantially different therefrom.
Particularly, use of porous carbonators is also suggested by applications of Mott Porous Metal Structures, pages 7, 9-11 of the Mott Metallurgical Corporation Catalog No. 1000, "Introduction to Engineering Controlled Porosity Products" but the application to beverage carbonation and the device described herein is not suggested.
Buchel U.S. Pat. No. 4,186,215 discloses a cup type of container having a pressure chamber at its base with a carbonation mixture therein such as sodium bicarbonate and citric acid. A permeable membrane covers the top of the chamber and allows water to slowly enter the chamber and carbon dioxide to pass therethrough in a pressure equalized reaction to carbonate a beverage over a sustained period of time. The membrane also prevents the resultant salts of the reaction from being absorbed in the beverage as the amount of water passing into the chamber is insufficient to accomplish this purpose. The operation of Buchel is substantially different from that of the present invention in terms of preventing resultant salts of the chemical reaction from contaminating a beverage.
Despite many attempts in the prior art to develop a system for the preparation of a satisfactory carbonated beverage in the home, none have succeeded in producing a carbonated product equal in flavor, taste, appearance, and quality and quantity of carbonation to commercially packaged, liquid carbonated beverages as are available in retail stores and supermarkets.